The common treatment for renal failure is hemodialysis treatment or peritoneal dialysis treatment. Both treatments utilize the diffusion of liquid through a semipermeable membrane. In the case of hemodialysis the membrane is in a dialyzer external to the patient, so that blood is withdrawn from the patient's vascular system and passed across the membrane while dialysis solution is passed across the other side of the membrane. Impurities in the blood are drawn through the membrane by osmotic pressure on the membrane and are disposed of in the discarded dialysis solution. In the case of peritoneal dialysis, the semipermeable membrane is the patient's peritoneal membrane. Dialysis solution is introduced into and retained for a period of time in the peritoneal cavity, and impurities in the blood migrate through the peritoneal membrane and into the dialysis solution. The dialysis solution with the impurities is then withdrawn from the peritoneal cavity and discarded into a "drain" bag or "collection" bag.
Both hemodialysis and peritoneal dialysis require significant amounts of dialysis solution, sometimes called dialysate. Common dialysates are primarily water, but with low ionic concentrations of dissolved sodium, potassium, calcium, magnesium, chloride, acetate, glucose and bicarbonate. The proportions of these and other compounds depends on a variety of factors. Regardless of the exact concentrations and relative proportions of the dissolved compounds, the main material in all dialysates is water.
Dialysis solutions have been premixed and prepackaged in a variety of mixes and sizes, so that the patient or the medical professional simply selects the desired size and mix of dialysate, makes the appropriate tubing connections to the prepackaged dialysates and to the patient and the dialysis machine, and then commences the procedure.
Regardless of the type of dialysis--peritoneal dialysis or hemodialysis--the procedure results in significant and sometimes substantial quantities of spent dialysis solution. This used dialysis solution has been exposed to and often contains a variety of pathogens including infectious diseases. There are cases in which used dialysis solution was found to contain viable HIV virus, for example, and there are undoubtedly other instances where used dialysis solution contained bacteria or viruses of other diseases as well.
This used dialysis solution is normally deemed "medical waste" and is required to be disposed of in accordance with applicable medical waste disposal procedures so as not to spread disease or contaminate water supplies. However, it is commonly recognized that the used dialysis solution is often disposed of improperly. Because many dialysis procedures are adapted for the convenience of home use, used dialysis solution is sometimes improperly discarded by simply putting it into trash receptacles for ordinary trash pick-up or pouring it into a sink or flushing it down the toilet. Even in hospitals and clinics, the high cost and inconvenience of medical waste disposal may tempt professionals to dispose of used dialysis solution improperly.
In the field of urinary catheters, there is a body of art pertaining to preventing pathogens from migrating from a urine collection bag up through a catheter and into the urethra. Such art is not directed toward the sterilization of the collected urine so that it can be properly disposed of without infecting others since urine does not normally contain infectious diseases even if from a diseased patient. Instead, this art is more directed toward preventing the collection bag from becoming a colonization site from which infection can migrate up the catheter to the patient himself. Illustrative of this urinary catheter art are U.S. Pat. No. 4,529,398 by Wong; U.S. Pat. No. 4,661,100 by Rechsteiner; U.S. Pat. No. 5,267,989 by Moyet-Ortiz; U.S. Pat. No. 4,863,445 by Mayhan; U.S. Pat. No. 4,417,892 by Meisch; and U.S. Pat. No. 4,372,313 by Villari.
The typical approach to preventing urinary tract infections in the urinary catheter prior art mentioned above is to include a sterilizing agent in the catheter or in the collection bag so that pathogens cannot migrate up the catheter. Such an approach is not appropriate for a dialysis collection bag, however, because in dialysis it is often desired to take specimen samples of the used dialysate. If the dialysate is sterilized upon entering the collection bag, then specimen samples cannot be cultured to test for live pathogens. It is also desirable in dialysis that the collection bag be entirely self-contained, so that the collection bag is manufactured with the sterilizing agent pre-placed within it to avoid a separate placement step at the time of use.
In the Wong patent, a dispensing device having a polymer with a chemoprophylactic agent is placed within the collection bag. The dispensing device begins sterilizing liquid in the collection bag immediately upon contact, and the device is designed such that the sterilizing properties continue for an extended period of time. In contrast, in dialysis collection bags it is desirable that the sterilization of the liquid not be commenced immediately upon contact with the dialysis collection bag, and in dialysis collection bags it is not necessary that the sterilization be contained for an extended period of time because the bag is filled in a very short period of time rather than over a period of many hours.
The Rechsteiner patent discloses a system with a urine collection bag having a fragile resinous material inside which is broken to release a sterilizing or diagnostic agent. The Rechsteiner patent is like the Wong patent in that it is designed for urinary catheter applications in which the collected urine must be sterilized immediately upon contact and over an extended period of time to prevent pathogen migration into the patient. The Mayhan patent is similar to the Rechsteiner patent, except that the resinous sterilizing agent is replaced with a slow-dissolving tablet. The Moyet-Ortiz patent discloses an antiseptic absorbent pad in a urine collection device; the Meisch patent discloses an outlet tube to a urine collection bag which is treated with a sterilizing agent to prevent pathogen colonization; the Villari parent discloses a urine collection bag with a tubular portion having a device for retaining an antimicrobial agent.